The present invention relates to an improved mapping catheter that is particularly useful for mapping electrical activity in a tubular region of or near the heart.
Atrial fibrillation is a common sustained cardiac arrhythmia and a major cause of stroke. This condition is perpetuated by reentrant wavelets propagating in an abnormal atrial-tissue substrate. Various approaches have been developed to interrupt wavelets, including surgical or catheter-mediated atriotomy. Prior to treating the condition, one has to first determine the location of the wavelets. Various techniques have been proposed for making such a determination. None of the proposed techniques, however, provide for measurement of the activity within a pulmonary vein, coronary sinus or other tubular structure about the inner circumference of the structure.
The present invention is directed to a catheter having a mapping assembly and a method for measuring electrical activity within a tubular region of or near the heart, e.g., a pulmonary vein, the coronary sinus, the superior vena cava, or the pulmonary outflow tract. The mapping assembly, which has a generally circular region with a series of spaced-apart electrodes mounted thereon, is positioned within the tubular region so that the electrodes are in contact with an inner generally circumferential surface inside the tubular structure.
In one embodiment, the invention is directed to a mapping catheter comprising an elongated tubular catheter body and a mapping assembly mounted at the distal end of the catheter body. The catheter body has an outer wall, proximal and distal ends, and at least one lumen extending therethrough. The mapping assembly comprises a tubular structure having a generally straight proximal region attached to the catheter body, a generally circular main region generally transverse and distal to the proximal region having an outer circumference, a transition region connecting the proximal region and the main region, and a generally straight distal region distal the main region, preferably extending substantially tangentially to the generally circular main region. The tubular structure comprises a non-conductive cover over at least the main region of the mapping assembly. The assembly further comprises a support member having shape-memory disposed within at least the main region of the mapping assembly. A plurality of spaced-apart electrodes are carried by the generally circular main region of the mapping assembly.
In another embodiment, the invention is directed to a method for mapping electrical activity within a tubular region of or near the heart, wherein the tubular region has an inner generally circumferential surface. The method comprises inserting the distal end of a catheter as described above into the heart. The outer circumference of the generally circular main region of the mapping assembly is contacted with the inner generally circumferential surface of the tubular region. The electrical activity within the tubular region is mapped with the electrodes of the generally circular main region. The method is particularly useful for mapping tubular regions such as pulmonary veins, the coronary sinus, the superior vena cava, and the pulmonary outflow tract.